Internal-combustion engine



Oct. 2l, 1930.

F. H,l CATHCART INTERNAL COMBUSTION ENGINEl 1924 5 Sheets-Sheet l f Original Filed No'v 12 Oct- 21, 1930 F. H. cATHcAR-r INTERNAL COMBUSTION ENGINE Original F'iled Nov. 12 1924 5 Sheets-*Sheet 2 www:

Oct. 21, 1930. F. H.' cATHcAl-'QTv INTERNAL coMEusToN ENGINE Original Filed Nov. '12, 1924 5 Sheets-Sheet .'5

v. 12, 1924 5 sheets-sheet 4 Oct. 2l, N30. FfH. cATHcART A INTERNAL COMBUSTION ENGINE Original Filed No 1 M GQ@ S Oct. 21, 1930.

F. H. CATHCART.

INTERNAL` COMBUSTIN ENGINE y originen F11ed Nov. 12, 1924 5 sheets-sheet 5 Patented Oct. 21, 19 3O UNITED STATES PATENT Iol-FicE FRANK H. CATHOART, OF ALEXANDRIA, VIRGINIA, ASSIGNOR TO THE OATHOART- CUSHMAN ROTARY MOTOR INCORPORATED, OF WASHINGTON, DISTRIOT OF COLUM BIA, A CORPORATION OF DELAWARE INTERNAL-comiiiisrron ENGINE Application med November' 12,1924, Serial No. 749,501. Renewed S'eptember, 1929.

My invention relates to rotary engines of the ty ein which a plurality 'of cylinders are caused) to bodily rotate as a unit about an axis parallel to the movement of the pistons by the action of the pistons upon a plate or disk disposed in a plano forming an angle other than a right angle with the axis of rotation of the cylinders.

The broad principle of operation on which the invention is based is well known and many attempts have' been made to practically apply it.

' My invention has as its principal object to .produce a practical rotary engine which is simple in construction and efficient in operation.

The most characteristic feature of 4my invention, briefly stated, is the entire absence of a connection positively interconnecting the cylinders and the disk for interdependent rotary motion. i

The more' specific objects of the invention will appear more clearly from the description in connection with the accompanying drawings in which Fig. 1 is a central longitudinal section through a motor unit embodying the invention;

Fig. 2 is a transverse section substantially on line 2 2, Fig. 1;

Fig. 3 is an end View of the exhaust manifold as seen in a direction at right angle to tion on line 7 7, Fig. 9, showing` on an enlarged scale detail disclosed in Fig. 1;

Fig. 8 is one end view; Fig. 9 is an opposite end view of timing gear mechanism for operating the admission and exhaust valves; and

Fig. 1() is a fragmentary sectional view ih owing a modification of a detail shown in At the very outset it may be understood that, although'the motor unit as shown and described is an internal combustion engine,

the inventiony is of more general .application tions from the central rotor mem er 2.and in conjunction therewith define one of the cylinders. Each c linder contains two pistons 4 and 4b respectively moving in opposite directions.

The rotor member 2 is a casting provide with conduits for the passa e of gas into an out of the cylinders and wit seats into which the cylinders are fitted.

As indicated in Figs. 1 and 2, rotor 2 has bores 1 f or the reception of the cylinder parts 1a and 1*. and recesses 1" defining gas spaces between opposed pistons. 1 leads a conduit 5 (Fig. 2) wliich terminates in valve chambers 6 and 7 which, in turn, are connected with conduits 8 and 9 for the incoming lgas and the exhaust gas, respectively.-

aft 3 has a bore 3 to form a gas as- The s sage and openings 3b and 3 throu h w ich the gas is admitted into it anddischargedv from it, respectively. Adjacent the openings 3" the shaft 3 is surrounded by a casin 0 constituting a gas admission chamber. the openings 3 the gas passes into a collection chamber or manifold 11 from whichthe conduits 8 branch of to the different valve chambers 6.

The conduits 9 direct the exhaust gas to a l circular exhaust manifold 12 from which it can escape through exhaust pipes 13 to a .muffler or through a cut-out 14 directly to the atmosphere, as will be explained later on.

The gas admission and the discharge of the exhaust gas are controlled by valves 15 andl 16, respectively, which, in the particular instance, are shown as ordinary poppet valves drawn by springs 15* and 16'* against their seats.

As will appear later bn, the valves 15 and 16 are operated byI special timing mecha- 10 Into each vrecessv Vil nism to intermittently admit the'gas from the conduits 8 and allow the exhaust gas to flow into the exhaust manifold 12 in cyclic order.

At their outer ends the cylinder parts 1b and 1l1 are supported in accurately spaced relation by plates 17 and-18. The parts lb and 1a preferably terminate in fianges 17EL and 18a seating against one side of the plates 17 and 18, while on the other side of the plates are disposed extensions 19 and 20 provided with flanges 19a and 20a which bear on the plates 17 and 18 in opposition to flanges 17 a and 18B. The opposed flanges are vrigidly interconnected and drawn up against'the plates v 17 and 18 by any suitable means.

vThe inner ends ofthe cylinder parts 1 and 1b are provided with flanges 2a which bear against the rotor 2 and are firmly secured thereto by screw bolts (notshown).

The rotor, the cylinders and the plates 17 and 18 thus form a rigid mechanical unit secured to and rotating with shaft 3.

tively.

Inwardly of the cylinders and concentrically with the shaft 3 are disposed cylindri- 'cal casings 22 connected by means of flanges 22a to the rotor 2 and the plates 17, 18, respectively. 'This casing permits lubrication of the shaft 3 and various mechanism, as will be more fully pointed out, while the cylinders are exposed to the air to be cooled thereby.

The most essentiall members ofthe motor are disks 25V and 26 and a special form of mechanism for interconnecting the same with the pistons 4 and 4".

The disks are mounted for rotation about axes inclined to the axis of the shaft 3. In the particular form of apparatus shown,'sta tionary plates 27 and 28 are provided with hubs 27a and 28a on Vwhich the disks are mounted by means of ball bearings `in any suitable manner. i

Into the inner ends ofthe hubs extend collars i 29 and 30 of bearing boxes 31 and 32, respectively, for the shaft 3. The bearing boxes 31 and 32 are rigidly secured to the hubs 27@l and 28a by means of long bolts 29a and 30EL which are drawn up against plates 27b and 28h, bearing against the plates 27 and 28, respec- The hubs define a central opening large enough to accommodate the shaft 3 passing obliquely through them and at the sides between the top and the bottom of the collars 29 and 30 there is sufficient room for the bolts 29a and 30a to pass between the hubs and the shaft 3. The bearings 31a and 32H are thus rigidly supported from the stationary frames -of which the plates 27 and 28 are parts.v

, As previously stated larrangements includvingka rotary cylinder frame and a disk or cus U s mounted for rotation about an axis incllned tothe axis of rotationof the cylinder frame are not new. The radically new feature characterizing my invention, however,

...s y 'i arranca is the particular form of connection between the pistons of the cylinders and the disks. l/Vhile the construction disclosed is not to be understood as representing the only feasible execution. of the idea on which the invention is based, it is what I at present consider as a preferred embodiment and as such affords a clear understanding of the broad principles of operation, and a fairly definite perception of all equivalents coming under consideration.

rIhe disks 25 and 26 are constructed to de.- fine substantially circular slide ways. These slide ways include principally smooth circular surfaces 25a and 26a on the disks 25 and 26, in contact with which are directly or indirectly kept the. outer ends of the pistons 4a and 4b. As shown, each piston end may carry a ball 34 bearing on a slide piece 35 provided in one face with a spherical con- 35 or generally away from the slide surface 25a or 26a by meansof a retaining element comprising a partly spherical shell 36 terminating in a circular flange 37. The flange 37 bears against circular overhanging shoulders 38 and 38u forming part of the disk. through an interposed washer or ring 39 of fiber or like wearing material. The combined thickness of the flange 37 and washer 39 is so chosen that shell 36 in engagement with the ball maintains the latter in contact with the surfact of the concavity, and the slide piece 35 in contact with the slide surface 25a or 26a.

For practical reasons I provide the shoulder 38 on a separate ring 40 which may be attached to the disk by means of bolts 41. As a matter of expedience I provide the ring 40 with bayonet slots 42 whereby the ring may be detached without entirely unscrewing the bolts. To remove the ring, it is only necessary to slightly unscrew the bolts and turn the ring until the enlargements of the slots are in alignment with the bolt heads, whereupon the ring may be slipped over the latter. The shoulder 38a is defined by a collar 47 which is screwed upon the hub 48 of the disk and secured thereon by a lock nut 49.

The ball 34 is preferably formed on a separate element having a screw-threaded plug 43 (Fig.'1) by means of which it may be screwed into the piston;

In Fig. 10 is shown a slight modification of the connection. A slide piece. 44 and a shell 45 are screwed upon each other, the flange 46 being provided on the slide piece 44.

The valves are operated by a timing mechanism shown on an enlarged scale in Figs. 7 8 and 9. Upon the shaft 3 is loosely mounted a tubular element 50 having a Worm 50a, which 50El is in mesh; with five pinions 52 spaced 72l '10 separation under working conditions.

The worm 50t is disposed adjacent to plate 18 within the rotor system and the inward motionof the tubular member 50 is limited by a disk member 57 mounted on the shaft 3 and bearing against the cylindrical casing 22. This disk member and the plate 18 are provided with openings 58 and 59, respectively, in which are movably dis osed bars 60 and 61." To a'ord a larger u1ding surface for 20 the blocks, the disk mem er 57 and the plate 18 are provided' with sleeves 62 and 63.` rlvhe bars 60 and 61 are in alignment with the cams 55 and 54, respectively.

AO'n the outer surface of the plate 18 are mounted rocker arms 64, one end of which bears upon bars 61, while the other end bears upon rods 65 movably mounted in bushings 65a and 65 on opposite sides of plate 18.

Rods 65 in turn are in alignment with and bear upon the stems of the exhaust lvalves 16.

To the bars 6() are attached rods 66,which extend through the gas space 11 and through plate 17 guided by bushings 67 and 671. On

v the outer'side of plate 17 are mounted rocker 35 arms 68, one end of which bears upon the ends of rods 66, while the other end bears upon `rods 69 extendin through the plate 17 and bushings 7 0 and 0", the rods 6 1n turn being in alignment with and bearing pon the stems of the admission valves 15.

The rotor frame 2 is provided with bores 72 leading into the gas spaces between opposilte pistgns and into the bores 72 extend spark p ugs On the exhaust manifold 12 is supported by means of insulator studs 74 an arcuate conductor 75 which is energized by a timing mechanism of usual type 76, the timing mechanism being driven from a worm 77 on shaft 3.t

rlihe current is conducted from a battery (not shown) to the timing mechanism and' from the vtiming mechanism by a conductor, 78 to the arcuate conductor 75. rlhe conductor is advantageously supported on a tie' rod 79 inter- J connecting the stationary plates 27 and 28.

The operation is as follows: The timing mechanism lfor the control of the gas ow is so adjusted that, the valves 15 are moved to open position at the proper '6 5 the gas spaces 2a and the opposing cylinders 1a and 1*,and then -compressed/in the usual l way during the compression stroke.

rlhe timmg device 76 is set to ignite the compressed mixture lat the desired moment.

`The currentjumps from the arcuate conductor.75 to the lead-in wire of the spark plug. The distance between ythe arcuate conductor andthe spark plug may be so chosen as to define a gap most` suitable for particular conditions. The length of the arcuate conductor is determined by the usual range of the spark adiustment, as will be lreadily understood.

e .gear ratio of the. worm 50? and the pinionsf52 is 1:2, i. e. durino" one revolution fof the pinions 52 as a unit about the axis of shaft 3 `in engagement with the stationary worm the pinions make half a revolution.

about their axes of rotation and during two revolutions about the axis ofshaft 3 they make one complete revolution about their own axesl of rotation. This is in accordance with the well kriown principles of operation of the four cy'cle \type engine. One cycle is completed during two revolutions of the rotor. The admission valves and the exhaust valves the required cyclic order. The cams 55 transmit motion'to the admission valves 15 through the rods 66, rocker arms 68 and rods 69, while the cams 54 transmit motiont the exhaust valves through the rocker arms 64 and the rods 65. The springs 15a a'nd'16a operate to ,are operatedA once during two revolutions in normally close the valves' and hold them in closed' position while the rocker arms open 80 on the stationary member 81, which in the particular instance is the end plate for the bearing 31, for adjustably holding the tlibular member 50 in any desired angular relation, preferably through an intermediate y tubular member 82 connected to the tubular member 50 by means of a clutch connection as indicated in dotted lines in Figs. 1 and 7. The set screw 81 impinges upon a split steel ring 83 so that mutilation of the tubular member 82 is avoided. To change the time relation of the valves it is only necessary to loosen the set screw, turn the tubular member to the desired extent andy draw up the set screw again.

While ordinarily the .exhaust gases are passed through pipes 13 to a muli'ler, li have hinged on the exhaust manifold and operable by means of a link 14" and a rod 14 which lili) y provided. a cut-out 14 including a plate 14,a

' tal principles of physics.

,tion to the disks.

the disks may be held stationary without essentially affecting the principle of operation of the motor as a whole. The disks 25 land 26 are in reality abutment plates defining inclined planes. Each impulse given to a piston by the expansive force of the gases is transmitted to the disks and translated into rotary movement of the rotor frame due to the reaction ofthe inclinedplane upon the pistons. The pistons virtually slide down the inclined plane in accordance with fundamenheld stationary, the ends of the pistons actually slide down the inclined plane of the disks to the end of the expansion stroke. Such an actual sliding movement, however, would incur considerable friction losses. so far as the reaction of the disks upon the pistons is concerned, it is immaterial whetherv the disks are stationary'or rotate, since the inclined plane is fixed in space and in reladriving action resulting from the friction but also has to do work. During one quarter of a cycle itzhas to push the piston back against the vforce 'due to the pressure of the exhaust gases. During another quarter of a cycle it has to pull out the piston to suck in the gas, and during another quarter of a cycle it has to compress the gas, and in all of these instances. it must also overcome piston friction. Due to the action of the various retarding forces upon the disk the latter in the particular instance where the angle of inclination of the disks is about 171/2 degrees, is caused to lag behind synchronous speed an amount which I have found to be about 9/8 during one revolution.

This retardation or` creeping in backward direction is also at least in part due to the following:

Since the projection of the circle in which the pistons move, upon the disks 25 and 26 defines ellipses, the peripheral velocity of the disk must vary if its angular velocity is the same as that of the rotor frame. Since the velocity, either angular or peripheral. must at any moment be the same for all five pistons, and since for a definite angular velocit-y of the disk at the same moment the peripheral velocity measured along the elliptical path being variable, can inherently not agree with If the disks are In reality,

A concurrent movement' that of some of the pistons, there must be during each revolution a relative motion between the slide piece 35 ofeach piston and the slide surfaces 25a and 26a respectively. During each revolution of the shaft 3 some j of thevpistons are driven outwardly on their ibut I do know as a fact that there is an actual slippage amounting to about 1% during each revolution in a machine actually built according to the principles of the invention.

Due to the eccentricity of the elliptical path, which varies with the angle of inclination of the disks 25.and 26, there must also be a relative motion between the slide pieces l35 and the slide surfaces 25a and 26 in radial direction and such relative motion must of course be equal to the amount offeccentricity or the difference between the long radius of lthe ellipse andthe short radius thereof.

Heretofore efforts have been made to take care of relative movement between the individual pistons and the disks by pivotal connections, and also by affording relative sliding motion in radial direction.

The arrangement herein described differs essentially from all such connections in that each piston is entirely free and independent of the disks-so far as the range of relative motion requires a mutual adjustment, and is absolutely free to assume that relative position which it tends to assume at each instant.

There is, above all, no strain between the pistons and the disks due to the variation of the velocity inherent in the elliptical path described by the ends of the pistons upon the disks. This is particularly of advantage ,when the engine works with 3, 5 or 6 cylinders. For instance, in the case of five cylinders, the power strokes begin at angular intervals of 144 degrees. Thus one stroke has not yet reached its end when another stroke is superimposed upon the disk. Two

pistons are therefore all the time acting upon the disk while, as previously explained, the velocity of points of the disk measured along the elliptical path referred to must vary. When, for instance, one' piston just starts on its explosion stroke, and the previously propelled piston is 144 degrees in advance of it, the latter must have the peripheral velocity of the other piston, since both are part of the same revolving body (rotor), whereas the peripheral velocity of the point at which the previously propelled piston bears on the disk must inherently have a smaller peripheral d pivotal movement relatively to the piston, the

vus

pistons may be given a maximum bearing surface, while the length of the motor unit may be a minimum.

While the invention is specific in character,

various changes may be made within the sco e of the disclosure.

ompensatlon for wear such as is bound to occur between the disks and 26, on the one hand, and the parts connecting the pistons to them, on the other hand, may be easily made by interposing shims rbetween the flanges 37 and the washers' 39.

Due to the recessional movement of the disk the wear meident to the interconnection 0f the pistons and the disks is uniformly distributed over the whole area of the slide way, i. e. over the slide surfaces 25a and 26n as well as the overhanging shoulders. Aside from the uniformity of wear there is the advantage that compensation for wear is necessar only after longer periods of operation.

he istons are free to angu arly move above `t eir own axis in the-cylinders and actually change their angularl ositions with the result that they 4wear uni ormly in the cylinders.

The firing order of the'cylinders is 1, 3, 5, 2, 4, i. e. ignition takes place at angular intervals of 144 degrees as previously suggested.

In the foregoing I have described one embodiment. of the invention. rl`here is obviously considerable latitude in respect 'to the details available for the execution of the invention.

I claim 1. A rotary en 'ne comprising a plurality of parallel cylin ers grouped about and cony nected to a revolubly mounted shaft reciprocating pistons in the cylinders, a disk mounted for rotation about an axis inclined to the shaft, and means interconnecting ythe said pistons and disk to prevent relative movement in axial direction while permitting unrestrainedrelative angular movement of the disk and the pistons about their respective axes of rotation.

2. A rotary en in e comprising a plurality of parallel cylin ers grouped about and connected to a revolubly mounted shaft, reciprocating pistons in the cylinders, a disk fja'lvaosa mounted for rotation about an axis inclined to the shaft, and means interconnecting the said pistons and disk to prevent relative movement in axial directionA while permitting universal motion of the ends of the pistons in the plane of the disk and'unrestrained relative angular movement of the disk and the pistons about their respective axes of rotation.

3. A rotary en ine comprising a plurality ofparallel cylin ers grouped about and connected to a revolubly mounted shaft reciprocating pistons in the`cylinders, a disk mounted for rotation about an axis inclined to the shaft, and a connection between the end of each piston and the disk permitting unrestrained motion of the iston ends in all directions of the plane o? the disk independently of the angular position of the disk about its axis of rotation while preventing relative movement of the pistons and the disk in4axal direction. 1 1

. rotar en 'ne comprising a ura ity of parallel cylindrs grouped about land connected to a revolubly mounted shaft reciprocating pistons in the cylinders, a disk ed for rotation about an axis inclined to the shaft and means for'connecting the pistons to the disk, said means including a ball and socket connection and a circular slide way on the disk permitting a limited radial movementof one of the elements of the connecting means in the plane of the disk and unrestrained movement thereof in the circular course of the slide way.A

5. In a rotary engine of the t pe described, a power shaft, a disk mounte for rotation about an axis inclined to the shaft, a circular slide way on the disk, having overhanging shoulders and a slide piece in the slide way having a retainin flange of a width smaller than the width o the slide way.

6. In a rotary en ine of the et'pe described, a power shaft, a isk mount for rotation about an axis inclined to the shaft, a circular slide wa having overhangin shoulders, and a sli e piece having means or confining it in the slide way, the slide piece being movable transversely of the slide way.

7. in a rotary engine of the type described, a disk and two rings detachably connected to mountthe disks, said rings defining concentricshoulders overhanging the disks/ and facing each other, thereby constituting a circular slide Way on the disk.

8. In a rotary engine of the type described, a disk and two rin s detachably connected to the disks, said rmgs defining concentric shoulders overhanging the disk and facing each other the outer of `said rings bein connected to the disk by means ofPbolts an bayonet slots. l

9. In a rotary engine of the class described, a. disk having a central hub, a ring on the hub defining a circular shoulder toward the face of the disk, a ring detachably mounted adjacent the periphery of the disk and having an inwardly extending Hange concentric With the ring on the hub, said flange cooperating with the ring on the hub to define ai circular slide Way on the disk.

n testimony whereof, I ax my signature.

FRANK H. CATHCART.. 

